/*

 * Licensed to the Apache Software Foundation (ASF) under one

 * or more contributor license agreements.  See the NOTICE file

 * distributed with this work for additional information

 * regarding copyright ownership.  The ASF licenses this file

 * to you under the Apache License, Version 2.0 (the

 * "License"); you may not use this file except in compliance

 * with the License.  You may obtain a copy of the License at

 *

 *     http://www.apache.org/licenses/LICENSE-2.0

 *

 * Unless required by applicable law or agreed to in writing, software

 * distributed under the License is distributed on an "AS IS" BASIS,

 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.

 * See the License for the specific language governing permissions and

 * limitations under the License.

 */

package com.bff.gaia.unified.runners.core;



import com.bff.gaia.unified.sdk.transforms.DoFn;

import com.bff.gaia.unified.sdk.transforms.windowing.BoundedWindow;

import com.bff.gaia.unified.sdk.transforms.windowing.PaneInfo;

import com.bff.gaia.unified.sdk.values.PCollectionView;

import com.bff.gaia.unified.sdk.values.TupleTag;

import org.joda.time.Instant;



import java.util.Collection;



/**

 * Interface that may be required by some (internal) {@link DoFn}s to implement windowing. It should

 * not be necessary for general user code to interact with this at all.

 *

 * <p>This interface should be provided by runner implementors to support windowing on their runner.

 *

 * @param <InputT> input type

 * @param <OutputT> output type

 */

public interface WindowingInternals<InputT, OutputT> {



  /**

   * Unsupported state internals. The key type is unknown. It is up to the user to use the correct

   * type of key.

   */

  StateInternals stateInternals();



  /** Output the value at the specified timestamp in the listed windows. */

  void outputWindowedValue(

	  OutputT output,

	  Instant timestamp,

	  Collection<? extends BoundedWindow> windows,

	  PaneInfo pane);



  /** Output the value to a tagged output at the specified timestamp in the listed windows. */

  <AdditionalOutputT> void outputWindowedValue(

	  TupleTag<AdditionalOutputT> tag,

	  AdditionalOutputT output,

	  Instant timestamp,

	  Collection<? extends BoundedWindow> windows,

	  PaneInfo pane);



  /**

   * Return the timer manager provided by the underlying system, or null if Timers need to be

   * emulated.

   */

  TimerInternals timerInternals();



  /** Access the windows the element is being processed in without "exploding" it. */

  Collection<? extends BoundedWindow> windows();



  /** Access the pane of the current window(s). */

  PaneInfo pane();



  /** Return the value of the side input for a particular side input window. */

  <T> T sideInput(PCollectionView<T> view, BoundedWindow sideInputWindow);

}